Ceramic reed relay



June 11, 1968 E, R. MYATT ETAL CERAMIC REED RELAY Filed Aug. 1, 1966 4 Sheets-Sheet 1 June 11, 1968 E, R. MYATT ETAL.

CERAMI C REED RELAY 4 Sheets-Sheet 2 Filed Aug. 1, 1966 im 1968 E. R. MYATT ETAL CERAMIC REED RELAY 4 Sheets-Sheet 5 Filed Aug. 1, 1966 E. R. MYATT ETAL June 11,1968

CERAMIC REED RELAY 4 sheets-sheet 4 Filed Aug. 1, 1966 United States Patent 3,388,354 CERAMIC REED RELAY Edward Ronald Myatt, Redbourn, and Ernest Frederick Loveland, London, England, assignors to International Standard Electric Corporation, New York, N.Y., a corporation of Delaware Filed Aug. 1, 1966, Ser. No. 569,120 Claims priority, application Great Britain, July 30, 1965, 32,742/ 65 24 Claims. (Cl. 335-151) The invention relates to electromagnetic relays having their contact making members hermetically sealed inside an enclosure and especially to a variety employing a fiat armature as a contact member.

According to the present invention there is provided a sealed-contact assembly which includes a hermetically sealed rectangular parallelepipedal capsule and two contact members of magnetically and electrically conductive material within the capsule, at least one of the contact members being movable relative to the other, and in which the contact members are sealed through the walls of the capsule to enable external electrical connections to the made thereto.

Embodiments of the invention will now be described with reference to the accompanying drawings, in which:

FIGS. 1A, 1B and 1C are respectively a plan view of a rectangular plate and armature; a sectional side elevation of a contact assembly incorporating the armature; and a plan view of a modified plate;

FIG. 2 is a sectional side elevation of a double-make contact assembly;

FIG. 3 is a sectional end elevation of two double make contact assemblies;

FIGS. 4A and 4B show respectively a front elevation and side elevation of a plate and associated fixed contact;

FIG. 5 is a side view of a modified armature arrangement and associated fixed contact;

FIG. 6 is a side elevation of a change-over contact;

FIGS. 7A and 7B show different contact arrangements which incorporate armature backstops;

FIGS. 8A to SC show respectively a plan view, side elevation and end elevation of a modified armature and associated fixed contact;

FIGS. 9 through 12 show multiple contact relays having different formations of contact assemblies;

FIG. 13 is a pictorial view of a preferred form of multiple contact relay;

FIGS. 14A and 14B are respectively an end eleva tion and sectional side elevation of a further multiple contact relay;

FIGS. 15A and 15B are respectively a plan view and sectional side elevation (at BB of FIG. 15A) of a portion of a matrix incorporating the contact assembly of FIGS. 1A to 1C; while FIGS. 16A and 16B are respectively a plan view and sectional side elevation (at C--C of FIG. 16A) of a matrix incorporating the contact assembly of FIG. 2.

Referring now to the drawings, FIGS. 1A and 1B show a contact assembly having a rectangular plate 1 of ferromagnetic material hermetically sealed between two caps 2 and 3 which form a rectangular parallelepiped capsule. The rectangular plate 1 has a slot which divides it into an inwardly projecting movable portion which forms the armature 4 of the relay and a fixed remainder portion. The caps 2 and 3 form an enclosure for an armature 4 and a fixed contact 5 on the end of ferromagnetic rod 6 heremetically sealed into the cap 3. In this arrangement the armature 4 is parallel to the longer sides of the plate and is as long as is conveniently possible. Thus the length of the armature is about equal to the longer dimension of the plate. Alternatively the armature could be ice arranged diagonally across the plate as illustrated in FIG. 1C. The armature is preferably made to extend as near as conveniently possible the distance between the two diagonally opposite corners of the plate.

The arrangement can be modified as shown in FIG. 2 to provide an assembly have two make contacts. A further rectangular plate 7 of ferromagnetic material is spaced from the plate 1 by a spacer 8 of electrically insulating material. Integral with the plate 7 is an armature 9 having a contact portion at its free end aligned with a fixed contact 10 carried on a. rod 11 hermetically sealed into the cap 2.

If several assemblies each having two make contacts are arranged side by side to form a multiple contact device then, as shown in FIG. 3, the spacer 8 can be made common to all the assemblies.

With the plates illustrated in FIGS. 1A and 1C the gap between the armature and surrounding border of the plate is made as narrow as possible. Then,'as illustrated in FIGS. 4A and 4B, an effective leakage path exists, for the flux generated on energization of a coil 23, between the end 21 of the armature 4 and the portion 22 of the plate bordering the armature.

Alternatively, increased flux in the gap between the fixed contact member and the adjacent portion of the armature can be obtained in the manner illustrated in FIG. 5 in which a member 24 of magnetic material is secured to the fixed end of the armature 4 and extends its length to overlap the armature at its free end; The member 24 provides a further path for the flux leaving the contact carrying portion of the armature. Instead of the member 24, one of the end caps of the enclosure can be utilized for the purpose, by being made of ferromagnetic material. If, however, the enclosure is to be wholly of electrically insulating material then this end cap would be a ferrite. A similar eifect could be obtained with the assemblies of FIGS. 2 and 3 by making the spacer member 8 of ferrite.

As illustrated in FIG. 6, the rectangular type contact assembly can be modified to operate as a change-over contact. A rectangular plate 31 is sandwiched between two ceramic end caps 32 and 33. The armature 34 is normally urged against a contact member 35 of non-magnetic material. The application of magnetic flux to the assembly attracts the armature 34 to a second contact member 36 of ferromagnetic material. In order to .ensure that the armature is urged against the member 35 with the required contact pressure, the contact bearing end of the member 35 is set to protrude beyond the plate contacting face of the cap 32 by a distance d, which is the amount by which the end of the armature 34 must be displaced to exert the required contact pressure against the member 35. The end of the member 36 is set short of the plate contacting face of the cap 33 by a distance of d-l-g, where g is the required distance betweenv the armature and the member 36 when the armature is in its rest position. Therefore, when the plate and caps are secured together, the armature is initially displaced by the member 35 towards the member 36 a distance equal to d and thus in its rest position remaining a distance g from the end of the member 36. i

In the case of the previously described single and double plate assemblies a back stop can be provided which is engaged by the armature on its return to its rest position to shorten the period during which the armature vibrates before coming to rest. FIGS. 7A and 7B illustrate two of the previously described constructions with aback stop provided. FIG. 7A is of the type having a ceramic cap 37 which has a back-stop in the form of a stud 38 which is secured to the recessed face of the cap. In the released position the armature 39 rests against the stud 38. The assembly of FIG. 7B is of the type having two plates 40 and 41 separated by a ceramic spacer 42. In this case the back-stops are in the form of studs 43 and 44 which are located on opposite sides of the spacer 42. In each of the constructions just described, the back-stop protrudes towards its armature sufficiently far for the armature to normally occupy a position nearer to the fixed contact than would otherwise be the case.

To reduce the likelihood of faulty operation of the contact assembly due to the contacts making poor electrical contact with each other, the ar-matures of the previously described plates and their respective fixed contacts may be modified as illustrated in FIGS. 8A to SC by providing a cylindrical end 45 to the fixed contact and a slot 46 in the free end of the armature. The end of the fixed contact has the axis of its cylindrical end across the width of the armature. When the contacts close the two portions 47 and 48 of the armature on either side of the slot 46 are attracted independently to the fixed contact. If, therefore, one portion of the armature makes poor contact there is a good possibility that a low resistance make between its other portion and the fixed contact will exist.

The contact assemblies that have been described can be formed into very compact multiple contact relays. Relays which are constructed from three such assemblies will now be considered with respect to the various formations in which the contact assemblies can be arranged.

Contact assemblies with their contacts equally spaced from the longitudinal axis of their respective assemblies are arranged in two abutting rows of two assemblies. As shown in FIG. 9 each of the stationary contact rods extends into a common energizing coil 49. If it is preferred for the spacing between the rods 5 to be as small as possible the contact assemblies are arranged with the rods 5 adjacent the centre of the formation as in FIG. 10. For this purpose the assemblies of FIG. would each have a plate whose armature at its free end lies on a diagonal of the rectangular caps.

FIGS. 11 and 12 are described for contact assemblies such as FIGS. 1 and 2, in which the rods 6 and 11 (only rods 6 shown in FIGS. 11 and 12) have a portion of their length perpendicular to the caps 2 and 3 (only the end caps 3 are shown in FIGS. 11 and 12) surrounded by an energizing coil 50.

In the formation of FIG. 11, the rectangular assemblies have their rods 6 adjacent the centre of the formation. The contact assemblies are arranged in mutually inwardly facing pairs, each pair forming one of the intersecting limbs of a right-angled cross. At the centre of the formation the assemblies can either abut at their edges, or can be chamfered, as indicated by the dotted lines, to further decrease the mutual spacing between the rods 6. In FIG. 12 two assemblies are located each side of one end of the energizing coil 50.

When the double contact assembly of FIG. 2 features in either of the just described formations, two axially aligned coils would be provided, one each for the rods 6 and 11 (FIG. 2).

One preferred construction for a multiple contact relay is illustrated in FIG. 13 in which two contact assemblies 51 and 52 are mounted side by side and extend through the centre of an energizing coil 53. The assemblies are of the type previously described with reference to FIG. 2 and like parts are identified by the same reference numerals as used in this earlier figure. A spacer plate 54 of electrically insulating material separates the two assemblies from each other. The assembly 51 is shown with a portion of its end cap 3 removed to expose the plate 1, armature 4 and the contact bearing end 5 of the rod 6. In the case of each assembly the spacer 8, plate 7, end cap 2 and rod 11 are also shown. For practical convenience only the fixed contact rods 6 and 11 are bent at right angles at the edges of one flange 55 of a coil former 56. Electrical connections to the rods and terminals 57 of the plates 1 and 7 can thus be made from one end of the relay. The overall dimensions of the relay are approximately Wide x 1" long x high. A similar relay construction could be obtained with the previously described single make contact assemblies illustrated in FIGS. 1A to 1C.

Referring now to FIGS. 14A and 14B, a multiple contact unit will now be considered in which four single contact assemblies are used and which are based on the type illustrated at FIGS. 1A and 1B. The plates 1 of the units are located each on a different side of a support member 58 of electrically insulating material. This support member takes the place of the end cap 2 (FIG. 1B) for each contact assembly. A shallow groove 61 is provided in each of the sides of the member 58 to provide clearance for the movement of the adjacent armature 4. The cap 3 of each assembly is secured to the support member 58 to provide a sealed enclosure for the armature 4 as previously described. Each of the plates being, there fore, firmly clamped between the member 58 and its re spective end cap 3. The multiple contact arrangement so formed has an energizing coil 62 located over the portion of each end cap 3 between the contact rod 6 and the opposite end of the cap.

The application of the sealed contact assemblies to a co-ordinate switching matrix such as used in telephone switching equipment will now be considered. It is assumed that a four-wire path through the matrix is to be established at each switching operation. The matrix consists of a number of rows of contact assemblies, and at each row the assemblies are in groups of four.

When the switching assemblies of the type shown in FIGS. 1A and 1B are to be used, one preferred form of construction of the groups of assemblies is shown in FIGS. 15A and 15B. Four contact assemblies 70, each having single make contacts are arranged two on each side of a coil 71 with their respective fixed contact extensions 6 led through the centre of the coil. A spacer plate 72 of electrically insulating material may be situated between the extensions on opposite sides of the coil. Further spacers 73 and 74 of insulating material are located between adjacent assemblies. The contact unit so formed is secured to the printed wiring board 76 with the extensions 75 to the plates 1 and the extensions 6 led through holes in the board 76 to its opposite side where they are connected to the appropriate printed conductors.

The wiring board '76 has parallel input conductors on the opposite side of the board to the contact units. The contact assemblies occupying the same numerical position in row of contact units are connected to the same one of these conductors. Four output conductors are provided for each row of contact assemblies. The output conductors are printed on the equipment side of the wiring board and are at right angles to the input conductors. At each point at which a contact assembly is to be connected to an output conductor, the conductor is extended through a hole to the opposite side of the board by e.g. a hollow rivet. This enables the contact assemblies to be connected to their appropriate input and output conductors from one side of the board. The contact assemblies from each group or contact unit within the row are connected to a different one of the four output conductors, each of the groups in the row being likewise connected to the same output conductors.

FIGS. 16A and 16B show a preferred matrix construction using contact assemblies of the type shown in FIG. 2. In this case two contact assemblies 81 are mounted in the centre of an energizing coil 82 with the fixed contact extensions 6 and 11 of each assembly 81 formed around the outside of the coil 82. The two assemblies are electrically insulated from each other by a spacer 83. The unit so formed is secured to the wiring circuit board 76 with the extensions 6 and 11 and the terminal extensions to the plates 1 and 7 passed through holes in the board to its opposite side where they are connected to the ap propriate printed conductors in the manner previously described.

Although the matrix embodiments that have been described make use of printed wiring boards, such boards are not an essential feature of the invention. The contact asstmblies could equally well be mounted on a plain base board and the crosspoint multiplying done by means of other known means such as ribbon cabling, conventional wiring or flexible printed wiring etc.

It is to be understood that the foregoing description of specific examples of this invention is made by way of example only and is not to be considered as a limitation on its scope.

What is claimed is:

1. A sealed contact assembly for a relay within a hermetically sealed rectangular parallelepiped capsule comprising, a rectangular fiat plate of ferromagnetic material, an armature formed from and integral with the plate, the armature extending in the direction of the longer pair of sides of the plate, the armature being substantially equal to the length of said sides, at least one fixed contact sealed through a wall of the capsule to co-operate with a contact portion at the unconnected end of said armature, and electrical connections to the plate and hence to said armature and to the fixed contact.

2. A sealed contact-assembly for a light current electromagnetic relay including a rectangular flat plate of ferromagnetic material, an armature formed from and integral with the plate, the armature extending in the direction of the longer pair of sides of the plate, the armature being substantially equal to the length of said sides, a cap of electrically insulating material sealed on each side of the plate to form therewith a rectangular parallelepiped capsule including a hermetically sealed enclosure between the caps, the interior surface of at least one of the caps being spaced from the armature to allow for its movement, and a rod of ferromagnetic material hermetically sealed through the last mentioned cap to provide a fixed contact member and magnetic pole piece cooperating with the movable contact member.

3. An assembly as claimed in claim 2, in which the armature extends parallel to the longest pair of sides of the plate.

4. An assembly as claimed in claim 2, in which the armature is arranged diagonally to the longest pair of sides of the plate.

5. An assembly as claimed in claim 2, in which the airgap separating the disconnected portion of the armature from the plate is made small compared with the width of said plate, the portion of the plate bordering on the armature thereby providing a further flux path between the contact bearing portion of the armature and the plate for increasing the effective flux in the air gap between the armature and the fixed contact.

6. An assembly as claimed in claim 2, in which a member of ferromagnetic material is secured to the armature at its fixed end on the opposite side of the armature to the fixed contact, which member extends parallel to the armature at least to a point opposite the fixed contact, which member is spaced from the armature over a substantial portion of its length, whereby said member provides a further flux path between the contact bearing portion of the armature and the plate diaphragm for increasing the effective flux in the air gap between the armature and said fixed contact.

7. An assembly as claimed in claim 2 and including a further fixed contact member of non-magnetic material hermetically sealed through the opposite cap to that which carries said rod of ferromagnetic material, the interior surface of both said caps being spaced from said armature to allow for its movement, said armature being normally spring urged into contact with said further fixed contact member.

8. An assembly as claimed in claim 2 and including a further rectangular plate of ferromagnetic material dimensionally similar to the first mentioned plate, the two plates being arranged parallel to each other and spaced apart by a member of electrically insulating material, each plate having sealed to one side thereof a different one of said caps, both caps having an internal surface spaced from the adjacent armature, and a further rod of ferro-magnetic hermetically sealed through the opposite cap to said last mentioned cap to provide a fixed contact member and magnetic pole piece co-oper-ating with the movable contact member of the further plate.

9. An assembly as claimed in claim 8, wherein the diaphragms are arranged with their movable contact members common to one end of said enclosure.

10. At least two assemblies as claimed in claim 8 arranged side by side wherein said member of electrically insulating material is common to each of said assemblies.

11. An assembly as claimed in claim 2, in which both caps are of ceramic material.

12. An assembly as claimed in claim 2 in which the cap behind the armature is provided with a back-stop for the armature, said stop being engaged by the unconnected end of the armature when the armature occupies its re leased position.

13. An assembly as claimed in claim 8 wherein said member of electrically insulating material is provided with a back-stop for each said armature, which stops are provided 1011 opposite side-s of the member, each of which stops is engaged by the unconnected end of the associated armature when said armature occupies its released position.

14. A multiple contact relay including at least two sealed contact assemblies as claimed in claim 1, in which the assemblies are arranged side by side in at least one row, each assembly having a portion of a fixed contact member external to the capsule located inside an energizing coil common to all the said assemblies.

15. A re-lay as claimed in claim 14, which relay includes four sealed contact assemblies, the assemblies being arranged in a rectangular abutting formation with the unconnected ends of their respective armatures extending towards the centre of said formation, the portions of said fixed contact members external to said enclosures being thereby spaced a minimum distance apart.

16. A multiple contact relay in which four sealed contact assembles such as are claimed in claim S, are arranged in two inwardly facing pairs, which pairs each 'form one of the intersecting limbs of a right-angled cross, the portions of their respective fixed contact members external to the capsules being arranged at a minimum distance apart, and which portions extend into an energizing coil common to all the said assemblies.

17. A multiple contact relay in which four sealed contact assemblies such as are claimed in claim 5, are arranged in two stacks each of two assemblies, the ends of the assemblies adjacent to their respective contact elements being inwardly facing and the stacks abutting at said ends, the portions of the fixed contact members external to their respective capsules being thereby spaced a minimum distance apart, and which portions extend into an energizing coil common to all the said assemblies.

18. A multiple contact relay in which two sealed contact assemblies as claimed in claim 8 are stacked side by side with the capsules extending through the centre of 'a common energizing coil and with the portions of the fixed contact members external to their respective capsules resting outside the common energizing coil.

19. A multiple contact relay comprising four sealed contact assemblies generally as claimed in claim 2, the plate to each assembly being sealed between the cap carrying its fixed cont-act member and a support member of electrically insulating material common to all the assemblies, which support member is of square crosssection, there being one plate and associated cap located on each of the sides of said support member, and an energizing coil surrounding the outwardly facing side of each of the caps over a portion of their length between the fixed contact members and the ends of the caps remote therefrom.

20. A co-ordinate switching matrix in which a sealed contact assembly as claimed in claim 2 is associated one to each co-ordinate point of said matrix, which matrix includes a support board of electrically insulating material having a first plurality of parallel arranged conductors on one side thereof, a plurality of scaled contact assemblies fixed to said board and arranged in rows, the contact assemblies of each row having their fixed contacts each electrically connected to a difierent one of said conductors, the assemblies which occupy the same numerical position in each row being connected to the same conductor, and a second plurality of conductors associated with the opposite side of said board to the first mentioned conductors, wherein the cont-act assemblies of each row are arranged in groups of the same number of assemblies the assemblies in each group being adapted to operate together, there being a corresponding number of second mentioned conductors to each said row as there are contact assemblies to a group, which conductors are each connected to the plate and hence the armature of a different contact assembly of each group in said row.

21. A matrix as claimed in claim 20 wherein the first and second plurality of conductors are printed conductors.

'22. A matrix as claimed in claim 20 wherein each said group comprises four sealed contact assemblies.

23. A matrix as claimed in claim 22, in which each of said groups comprises four contact assemblies and an energizing coil common thereto, there being two of the assemblies supported on each side of said coil, and each of the assemblies having that portion of its fixed contact extending outside said enclosure led through said energizing coil to said board.

24. A matrix as claimed in claim 20, in which each said group comprises two contact assemblies and an energizing coil common thereto, said assemblies being situated inside said coil, with the coil located between said board and the portions of the fixed contacts extending beyond their respective enclosures to said board, each of which portions is bent substantially parallel to the adjacent side of said coil.

References Cited FOREIGN PATENTS 2/1966 Great Britain. 4/1966 Great Britain. 

1. A SEALED CONTACT ASSEMBLY FOR A RELAY WITHIN A HERMETICALLY SEALED RECTANGULAR PARALLELEPIPED CAPSULE COMPRISING, A RECTANGULAR FLAT PLATE OF FERROMAGNETIC MATERIAL, AN ARMATURE FORMED FROM AND INTEGRAL WITH THE PLATE, THE ARMATURE EXTENDING IN THE DIRECTION OF THE LONGER PAIR OF SIDES OF THE PLATE, THE ARMATURE BEING SUBSTANTIALLY EQUAL TO THE LENGTH OF SAID SIDES, AT LEAST ONE FIXED CONTACT SEALED THROUGH A WALL OF THE CAPSULE TO CO-OPERATE WITH A CONTACT PORTION AT THE UNCONNECTED END OF SAID ARMATURE, AND ELECTRICAL CONNECTIONS TO THE PLATE AND HENCE TO SAID ARMATURE AND TO THE FIXED CONTACT. 